{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-33557","assignerOrgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","state":"PUBLISHED","assignerShortName":"apache","dateReserved":"2026-03-23T03:14:53.527Z","datePublished":"2026-04-20T13:28:43.669Z","dateUpdated":"2026-06-30T12:07:33.565Z"},"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Apache Kafka","vendor":"Apache Software Foundation","versions":[{"lessThanOrEqual":"4.1.1","status":"affected","version":"4.1.0","versionType":"semver"}]}],"credits":[{"lang":"en","type":"finder","value":"Павел Романов <promanov1994@gmail.com>"}],"descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<div>A possible security vulnerability has been identified in Apache Kafka.</div><div>By default, the broker property `sasl.oauthbearer.jwt.validator.class` is&nbsp;set to `org.apache.kafka.common.security.oauthbearer.DefaultJwtValidator`. It accepts any JWT token without validating its&nbsp;signature, issuer, or audience. An attacker can generate a JWT&nbsp;token from any issuer with the `preferred_username` set to any user, and the broker will accept it.</div><div>We advise the Kafka users using kafka v4.1.0 or v4.1.1 to set the config `sasl.oauthbearer.jwt.validator.class` to `org.apache.kafka.common.security.oauthbearer.BrokerJwtValidator` explicitly to avoid this vulnerability. Since Kafka v4.1.2 and v4.2.0 and later, the issue is fixed and will correctly validate the JWT token.</div><br>"}],"value":"A possible security vulnerability has been identified in Apache Kafka.\n\nBy default, the broker property `sasl.oauthbearer.jwt.validator.class` is set to `org.apache.kafka.common.security.oauthbearer.DefaultJwtValidator`. It accepts any JWT token without validating its signature, issuer, or audience. An attacker can generate a JWT token from any issuer with the `preferred_username` set to any user, and the broker will accept it.\n\nWe advise the Kafka users using kafka v4.1.0 or v4.1.1 to set the config `sasl.oauthbearer.jwt.validator.class` to `org.apache.kafka.common.security.oauthbearer.BrokerJwtValidator` explicitly to avoid this vulnerability. Since Kafka v4.1.2 and v4.2.0 and later, the issue is fixed and will correctly validate the JWT token."}],"metrics":[{"other":{"content":{"text":"important"},"type":"Textual description of severity"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-1285","description":"CWE-1285 Improper Validation of Specified Index, Position, or Offset in Input","lang":"en","type":"CWE"}]}],"providerMetadata":{"orgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","shortName":"apache","dateUpdated":"2026-04-20T13:28:43.669Z"},"references":[{"tags":["vendor-advisory"],"url":"https://kafka.apache.org/cve-list"},{"tags":["mailing-list"],"url":"https://lists.apache.org/thread/v57o00hm6yszdpdnvqx2ss4561yh953h"}],"source":{"discovery":"UNKNOWN"},"title":"Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication","x_generator":{"engine":"Vulnogram 0.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/04/17/2"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2026-04-20T13:38:51.117Z"}},{"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":9.1,"attackVector":"NETWORK","baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-04-20T14:29:31.424817Z","id":"CVE-2026-33557","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-04-20T14:30:30.936Z"}},{"affected":[{"cpes":["cpe:/a:redhat:debezium:3"],"defaultStatus":"affected","product":"Red Hat build of Debezium 3","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:amq_streams:3"],"defaultStatus":"affected","product":"streams for Apache Kafka 3","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:serverless:1"],"defaultStatus":"unaffected","product":"OpenShift Serverless","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:camel_quarkus:3"],"defaultStatus":"unaffected","product":"Red Hat build of Apache Camel 4 for Quarkus 3","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:camel_spring_boot:4"],"defaultStatus":"unaffected","product":"Red Hat build of Apache Camel for Spring Boot 4","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:service_registry:2"],"defaultStatus":"unaffected","product":"Red Hat build of Apicurio Registry 2","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:apicurio_registry:3"],"defaultStatus":"unaffected","product":"Red Hat build of Apicurio Registry 3","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:debezium:2"],"defaultStatus":"unaffected","product":"Red Hat build of Debezium 2","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:quarkus:3"],"defaultStatus":"unaffected","product":"Red Hat build of Quarkus","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:jboss_data_grid:8"],"defaultStatus":"unaffected","product":"Red Hat Data Grid 8","vendor":"Red Hat"},{"cpes":["cpe:/o:redhat:enterprise_linux:8"],"defaultStatus":"unaffected","product":"Red Hat Enterprise Linux 8","vendor":"Red Hat"},{"cpes":["cpe:/o:redhat:enterprise_linux:9"],"defaultStatus":"unaffected","product":"Red Hat Enterprise Linux 9","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:jboss_fuse:7"],"defaultStatus":"unaffected","product":"Red Hat Fuse 7","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:7"],"defaultStatus":"unaffected","product":"Red Hat JBoss Enterprise Application Platform 7","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:jboss_enterprise_application_platform:8"],"defaultStatus":"unaffected","product":"Red Hat JBoss Enterprise Application Platform 8","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:jbosseapxp"],"defaultStatus":"unaffected","product":"Red Hat JBoss Enterprise Application Platform Expansion Pack","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:jboss_enterprise_bpms_platform:7"],"defaultStatus":"unaffected","product":"Red Hat Process Automation 7","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:amq_streams:2"],"defaultStatus":"unaffected","product":"streams for Apache Kafka 2","vendor":"Red Hat"}],"datePublic":"2026-04-20T13:28:43.669Z","descriptions":[{"lang":"en","value":"A flaw was found in Apache Kafka. By default, the `sasl.oauthbearer.jwt.validator.class` property is set to `org.apache.kafka.common.security.oauthbearer.DefaultJwtValidator`, which does not validate JSON Web Token (JWT) signatures, issuers, or audiences. A remote attacker can exploit this by crafting a malicious JWT token with an arbitrary `preferred_username`, leading to an authentication bypass and unauthorized access to the Kafka broker."}],"metrics":[{"other":{"content":{"namespace":"https://access.redhat.com/security/updates/classification/","value":"Important"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":8.6,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-303","description":"Incorrect Implementation of Authentication Algorithm","lang":"en","type":"CWE"}]}],"references":[{"tags":["vdb-entry","x_refsource_REDHAT"],"url":"https://access.redhat.com/security/cve/CVE-2026-33557"},{"name":"RHBZ#2459739","tags":["issue-tracking","x_refsource_REDHAT"],"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2459739"},{"tags":["x_sadp-csaf-vex"],"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33557.json"}],"timeline":[{"lang":"en","time":"2026-04-20T14:01:07.601Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-04-20T13:28:43.669Z","value":"Made public."}],"title":"kafka: Apache Kafka: Authentication bypass via improper JWT validation","x_adpType":"supplier","x_generator":{"engine":"sadp-cli 1.0.0"},"providerMetadata":{"orgId":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","shortName":"redhat-SADP","dateUpdated":"2026-06-30T12:07:33.565Z"}}]}}